This invention is generally directed to developer compositions, and more specifically, the present invention relates to developer compositions with coated carrier components, or coated carrier particles that can be prepared by, for example, dry powder processes. More specifically, the present invention relates to compositions, especially carrier compositions compromised of a core, and thereover a ferrocene containing polymer, or polymers.
In embodiments of the present invention, the carrier particles are comprised of a core with a coating thereover of a ferrocene containing polymer such as a poly (ferrocenyl silane), or a poly(ferrocenyl phosphane), or more specifically poly(ferrocenyl dialkyl such as methylsilane) or poly(ferrocenyl aryl, such as phenylphosphane), and wherein the polymers selected can be conductive and thus there is avoided the need to add to the polymer a conductive component such as carbon black. The carrier may include the polymer coating thereover in admixture with other suitable polymers, and more specifically, with a second polymer, such as a fluoropolymer, polymethylmethacrylate, poly(urethane), especially a crosslinked polyurethane, such as a poly(urethane)polyester and the like, and moreover, the copolymer coating may contain a conductive component, such as carbon black, and which conductive component is preferably dispersed in the polymer coating. With the conductive component, there can be enabled carriers with increased developer triboelectric response at relative humidities of from about 20 to about 90 percent, improved image quality performance, excellent high conductivity ranges of from about 10.sup.-10 to about 10.sup.-7 (ohm-cm).sup.-1, and the like. An important advantage associated with the carriers of the present invention with the polymer coating thereover include a high triboelectrical charge, for example a carrier tribo range of from about a plus (positive charge) or negative charge of about 10 to about 70, and preferably from about 15 to about 50 microcoulombs per gram, and most preferably from about 15 to 40 microcoulombs per gram and which carriers possess a conductivity of, for example, from about 10.sup.-6 to about 10.sup.-13 and preferably from about 10.sup.-8 to about 10.sup.-11 and which conductivity is measured by a magnetic brush conducting cell.
The carrier particles of the present invention can be selected for a number of different imaging systems and devices, such as xerographic copiers and printers, inclusive of high speed color xerographic systems, printers, digital systems, combination of xerographic and digital systems, and wherein colored images with excellent and substantially no background deposits are achievable. Developer compositions comprised of the carrier particles illustrated herein and prepared, for example, by a dry coating process are generally useful in electrostatographic or electrophotographic imaging systems, especially xerographic imaging and printing processes, and digital processes. Additionally, the invention developer compositions comprised of substantially conductive carrier particles are useful in imaging methods wherein relatively constant conductivity parameters are desired. Furthermore, in the aforementioned imaging processes the triboelectric charge on the carrier particles can be preselected, which charge is dependent, for example, on the polymer composition and dispersant component applied to the carrier core, and optionally the type and amount of the conductive component selected.